Apparatus for controlling dispensing of molten metal

ABSTRACT

An apparatus for dispensing molten metal including means for transferring metal from a charging reservoir which may be part of a metal melting furnace to a dispensing chamber by fluid pressure such as compressed air, a supply passage means through which the molten metal is transferred from the charging reservoir to the dispensing chamber and dispensing passage means for transferring molten metal from the dispensing chamber, with both passage means being made of heat conducting material resistant to the molten metal and in thermal contact therewith. The heat conducting supply passage means is in thermal contact with the molten metal in both the reservoir and chamber.

United States Patent Acker et al. Sept. 5, 1972 [54] APPARATUS FOR CONTROLLING FOREIGN PATENTS OR APPLICATIONS DISPENSING 0F MOLTEN METAL 397,158 2/1966 Switzerland ..l64/306 [72] Inventors: John N. Acker, Hoffman Estates;

Carl H. Ulbrich, Northbrook, both Primary Examiner-J. Spencer Overholser 0 Assistant Examiner-John E. Roethel [73] Assignee: 0. H. Warwick Company, Attorney-Hofgren, Wegner, Allen, Stellman & Mc-

Cord [22] Filed: Nov. 24, 1970 21 Appl. No.1 92,433 [57] ABSTRACT An apparatus for dispensing molten metal including 52 us. Cl ..266/38, 164/335 means transferring metal mm a charging 51 1111.01. ..C21b 7/14 be F melting furnace a 58 Field Of Search ..266/38; 222/1910. 12; 164/335, dspensmg chamber by Pressure 164/337, 133, 1 19, 306 pressed at, a supply passage means through WhlCh the molten metal is transferred from the charging reser- [56] References Cited voir to the dispensing chamber and dispensing passage means for transferring molten metal from the UNITED STATES PATENTS dispensing chamber, with both passage means being made of heat conducting material resistant to the mo]- iiiil 251333 3212111;;517::jijjjjjijff ii ten a and in thermal wmacwherewith- The heat 3:471:05? 10/1969 Solheim ..164/306 UX mnductmg supply passage means thermal contact lgllllllllllllm with the molten metal in both the reservoir and chamber.

6 Claims, 3 Drawing Figures APPARATUS FOR CONTROLLING DISPENSING OF MOLTEN METAL BACKGROUND OF THE INVENTION It has been proposed to dispense molten metal from a melting furnace by compressed air to force the metal in selected amounts, depending upon the duration of the air pressure, from a dispensing chamber that is supplied with metal from a reservoir in the furnace. The apparatus of this invention although relating generally to this type of apparatus incorporates improvements and advances that makes it reliable, easy to operate, easy to clean and permits complete surveillance of the interior of the metal dispensing portions of the apparatus at all times.

One of the features of this invention therefore is to provide an improved dispensing apparatus for molten metal having improved means for heating the metal in the supply passage by heat received from the molten metal and having means for protecting the passages against damage.

Another feature of the invention is to provide such an apparatus in which the supply passage as well as the dispensing passage are both straight for easy cleaning and for good heat conducting and each has means for observing the interior of the passage from the exterior of the apparatus when they are free of molten metal.

Other features and advantages of the invention will be apparent from the following description of one embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view through the center of a molten metal furnace embodying the invention.

FIG. 2 is a fragmentary plan view of one end of the furnace of FIG. 1.

FIG. 3 is a fragmentary sectional view taken substantially along line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The furnace may be heated by any means desired (not shown) to maintain a supply 11 of molten metal in a charging reservoir 12 portion of the furnace.

Separating the charging reservoir 12 from a dispensing chamber 13 at one end 14 of the furnace is a generally vertical wall 15 of heat conducting and molten metal resistant material such as silicon carbide.

Located in the wall 15 as a part thereof and integral therewith is a substantially straight passage 16 forming a supply passage having an entrance 17 spaced above the bottom of the reservoir 12 and an exit 18 spaced below the top of the dispensing chamber 13. A can be seen from FIG. 1, the passage 16 is inclined from the vertical in the direction of the top of the dispensing chamber 13 so that the exit 18 is elevated a considerable distance above its entrance 17. Both the entrance l7 and exit 18 are beneath the normal molten metal surface 19 in the reservoir 12 and surface 20 in the dispensing chamber 13. Under conditions of equal pressure the levels 19 and 20 will of course be at the same height.

The furnace 10 is lined with refractory insulation 21 on all sides as is customary in this art. The furnace is alsoprovided with the customary drain outlet 22 adjacent the bottom on one side and a counterbalanced access and skim door 23 also of conventional construction. This door is counterbalanced by weights 24 so that it may be easily moved between the closed solid line position and the raised broken line position shown in FIG. 1 for easy access to the interior of the furnace 10.

Located within the refractory insulation 21 at the end 14 of the furnace is means embodied in a metal resistant heat conducting tube 25 forming a dispensing passage 26 for dispensing molten metal from the dispensing chamber 13. This dispensing passage tube 25 has an entrance 27 at a level between the levels of the entrance l7 and exit 18 of the supply passage 16 and thus below the surface 20 of the molten metal. The dispensing passage tube 25 has an exit 28 externally of the dispensing chamber 13 and at a level above that of the supply passage exit 18.

The dispensing tube 25 is substantially entirely enclosed within the insulation 21 of the end 14 of the furnace except for a lower end portion 29 of the tube 25 containing the entrance 27.

The exit 28 of the dispensing passage 26 is located at the bottom 30 of a bowl-shaped cavity 31 at the top of the refractory insulation 21 of the end wall 14. This cavity 31 has an open top 32 and communicates with a downwardly and outwardly sloped trough 33 at the level 34 well above the dispensing passage 26 exit 28. This trough 33 is formed in the top surface of a downwardly and outwardly sloped section 35 of insulating material. Thus as can be seen from this description the bowl-shaped cavity means 31 comprises an extension of the dispensing passage 26 and the cavity 31 as well as the trough 33 comprise a portion of insulated wall 21 and the extension 35 thereof.

The reservoir and chamber separating wall 15, the enlargement thereof containing the supply passage 16 and the tube 25 containing the dispensing passage 26 are all constructed of heat conducting refractory material such as silicon carbide that is also resistant to destructive action by the molten metal. Furthermore, both passages 16 and 26 are straight between their entrances and exits for easy of cleaning and to aid in observing the passages for possible damage and for other purposes.

The top 36 of the end 14 of the furnace is provided with a removable cover 37 normally retained in air tight position as shown in FIG. 2 by releasable retainers 38. This cover 37 has mounted thereon an upwardly extending tube 39 that is axially aligned with the supply passage 16. This tube 39 is provided on its upper end with a transparent heat resistant viewing port 40 that may comprise heat resistant glass. This tube 39 containing the viewing port 40 permits viewing the supply passage 16 for inspection thereof when it is free of molten metal.

Extending laterally of the tube 39 at an area between the cover 37 and viewing port 40 is an air pipe 41 forming a part of the conventional compressed air supply system.

The supply passage 16 having both its entrance and its exit below the normal level 19-20 of the molten metal automatically provides metal in the dispensing chamber 13 so long as the liquid surfaces are at their normal height above the exit 18 and so long as the pressures on these levels are the same.

The operation of this invention is as follows.

With the liquid levels 19 and 20 as indicated above the exit 18 of the supply passage 16 low pressure such as -18 inches of water gauge is provided on the surface by air through the pipe 41. This pressure applied to the surface 20 depresses this level to just below the exit 18 of the supply passage 16. The metal so displaced from the dispensing chamber 13 is returned to the reservoir 12 by downward flow through the passage 16. This application of pressure causes the metal to surge up the dispensing passage 26 but is absorbed or dissipated in the cavity 31. The bottom of this cavity 31 is at a level substantially coinciding with the normal metal level 19-20.

Depressing the metal slightly below exit 18 forces metal up the dispensing passage 26 and into the cavity 31 to a point slightly below the lip 34 of the cavity 31. The metal is now in a ready or prepressured position.

After the level 20 in the chamber 13 has been thusly depressed to slightly below the passage exit 18, high pressure air is admitted through the pipe 41 for a preselected time which is equivalent to the size of the desired resulting shot of metal. This application of high pressure air which for example may be 20-30 inches of water gauge depresses the level of metal in the dispensing chamber 13 still further and forces the portion or shot of metal up the passage 26 and into the bowl-shaped cavity 31 for flow outwardly and downwardly in the trough 33 into the casting equipment (not shown). This application of high pressure is in timed successive increments each of equal duration and pressure to produce successive shots of molten metal of equal size depending on the duration of each successive application of high pressure air.

The cavity 31 accepts and slows down the velocity of the metal coming from the dispensing passage. This amounts to the cavity 31 being an expansion chamber to tame any surge.

Each successive shot is terminated by interrupting all air pressure to the dispensing chamber 13 including venting to atmosphere the air pressure in the pipe 41. This causes the metal in the bowl-shaped cavity 31 and the dispensing passage 26 to flow back by gravity into the chamber 13 and a fresh supply of metal from the reservoir 12 flows into the chamber 13 through the supply passage 16 as already described. This prepares the apparatus for the next shot of metal.

As is obvious from the above, each succeeding shot of molten metal will be delivered from a slightly lower level 19-20 than the preceding shot because each shot removes a small portion of metal from the furnace. Because the initial low pressure air always depresses the level 20 to slightly below the passage exit 18 the high pressure shot dispensing is not affected by the lowering metal level so that successive shots are of substantially the same size as preselected by the duration of the application of high pressure air. However, when the normal level 19-20 in the furnace reaches the passage exit 18 thereby preventing a subsequent equalized refilling of the chamber 13 it is necessary that the furnace itself be charged with additional metal to permit the castin ope ation to continue.

The appara us 0 this invention can be used with any ing: means comprising an insulating wall forming a.

dispensing chamber for retaining a supply of said molten metal preparatory to dispensing; means forming a charging reservoir for holding a heated mass of said molten metal; a heat conducting wall separating said chamber and reservoir for supplying heat through said wall to said molten metal supply from said heated mass; heat conducting means forming a supply passage in said heat conducting wall receiving heat from the molten metal, said passage having an entrance communicating with said reservoir and an exit elevated above said entrance communicating with said dispensing chamber, both the entrance and exit being beneath the liquid levels in the reservoir and chamber; heat conducting dispensing passage means forming a dispensing passage having an entrance in said dispensing chamber at a level between the levels of the entrance and exit of said supply passage and an exit externally of said dispensing chamber and above said supply passage exit; and means for providing pressure to the surface of molten metal in said dispensing chamber for initially depressing said molten metal surface substantially to the level of said supply passage exit and thereafter expelling a portion of said molten metal through said dispensing passage.

2. The apparatus of claim 1 wherein said heat conducting dispensing passage means is substantially entirely enclosed by said insulating wall except for an end portion of said dispensing passage means that is within said dispensing chamber.

3. The apparatus of claim 1 wherein said supply passage means is substantially straight for ease of cleaning, said dispensing chamber means comprises a cover and there is provided a viewing port member on said cover aligned with said supply passage for observing the same.

4. The apparatus of claim 3 wherein said viewing port member also contains said means for providing pressure.

5. The apparatus of claim 1 wherein said dispensing passage comprises means forming a bowl-shaped cavity into which said passage empties serving as an expansion chamber for accepting flowing metal, and a trough for said molten metal communicating with said bowlshaped cavity only at a level above the bottom of the cavity and above the exit of said dispensing passage.

6. The apparatus of claim 5 wherein said bowlshaped cavity means comprises a portion of said dispensing chamber insulation wall. 

1. Apparatus for dispensing molten metal, comprising: means comprising an insulating wall forming a dispensing chamber for retaining a supply of said molten metal preparatory to dispensing; means forming a charging reservoir for holding a heated mass of said molten metal; a heat conducting wall separating said chamber and reservoir for supplying heat through said wall to said molten metal supply from said heated mass; heat conducting means forming a supply passage in said heat conducting wall receiving heat from the molten metal, said passage having an entrance communicating with said reservoir and an exit elevated above said entrance communicating with said dispensing chamber, both the entrance and exit being beneath the liquid levels in the reservoir and chamber; heat conducting dispensing passage means forming a dispensing passage having an entrance in said dispensing chamber at a level betweeN the levels of the entrance and exit of said supply passage and an exit externally of said dispensing chamber and above said supply passage exit; and means for providing pressure to the surface of molten metal in said dispensing chamber for initially depressing said molten metal surface substantially to the level of said supply passage exit and thereafter expelling a portion of said molten metal through said dispensing passage.
 2. The apparatus of claim 1 wherein said heat conducting dispensing passage means is substantially entirely enclosed by said insulating wall except for an end portion of said dispensing passage means that is within said dispensing chamber.
 3. The apparatus of claim 1 wherein said supply passage means is substantially straight for ease of cleaning, said dispensing chamber means comprises a cover and there is provided a viewing port member on said cover aligned with said supply passage for observing the same.
 4. The apparatus of claim 3 wherein said viewing port member also contains said means for providing pressure.
 5. The apparatus of claim 1 wherein said dispensing passage comprises means forming a bowl-shaped cavity into which said passage empties serving as an expansion chamber for accepting flowing metal, and a trough for said molten metal communicating with said bowl-shaped cavity only at a level above the bottom of the cavity and above the exit of said dispensing passage.
 6. The apparatus of claim 5 wherein said bowl-shaped cavity means comprises a portion of said dispensing chamber insulation wall. 